Jon Holl-Allen KC

Call 1990 | Silk 2018

Jon Holl-Allen KC | Call 1990 | Silk 2018

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Jonathan is a highly-regarded barrister with a wealth of experience and knowledge in this field. He represents both claimants and defendants in cases ranging from straight-forward to extremely complex. Chambers & Partners note that he is “very sharp, bright and takes a forensic approach, which makes him extremely good in complex clinical cases.” 

“He is a very experienced clinical negligence practitioner who has an excellent grasp of detail.”

Chambers & Partners

Jonathan is a contributing editor of the Medical Law Reports.

Experience & Expertise

Jon has been instructed in clinical negligence cases for 30 years.  In the years before the coming into force of the CPR, when trials were more prevalent, he acquired a significant amount of trial experience in this field as sole counsel.  Throughout his career he has acted for claimants and for defendants on the instructions of NHSR, defence organisations and insurers.  He has extensive experience of dental claims, complemented by his experience of clinical cases in the dental disciplinary field.  In silk the focus of his practice is on high value and/or complex claims: he is regularly instructed in obstetric and other brain damage cases whose capital value exceeds £10m.

As is well known, full trials in this field are relatively rare, but Jon’s trial experience cases involving obstetrics, gynaecology, cardiology, ophthalmology, emergency medicine, the acquisition and treatment of MRSA infection in a patient undergoing orthopaedic surgery, ophthalmology, neurology and dentistry.  In clinical negligence trials he draws on his experience of calling and cross-examining medical expert witnesses in the course of his regulatory practice.  Issues of substantive law on which he has advised extensively include vicarious liability and non-delegable duties in the healthcare sector, and liability for psychiatric injury to secondary victims in the medical context.

Jon has substantial experience of medical inquests, including many in which ECHR art 2 has been (arguably) engaged and/or in which neglect or unlawful killing has been a potential verdict.  He has seen the inquest process from the perspective of families, individual healthcare practitioners and healthcare Trust and has been involved in cases in which the outcome of an inquest has had a bearing on, or led to, subsequent disciplinary proceedings.

cases & work of note

Kennedy v Frankel [2019] EWHC 106 (QB): consultant neurologist alleged to have provided negligent advice to patient on dopamine agonist medication for suspected Parkinson’s disease who developed symptoms of impulse control disorder.  Jon appeared on behalf of the successful claimant.

Bradfield-Kay v Cope [2020] EWHC 1351 (QB): allegations against a consultant orthopaedic surgeon that hip replacement surgery had been performed negligently: Jon was instructed on behalf of the defendant surgeon.

W v X NHS Trust (2021): Jon represented the claimant in an adult brain injury case in which the claimant was in receipt of substantial continuing healthcare (CHC) funding and the settlement therefore needed to address the issue of double recovery.

XYA v Great Ormond Street Hospital NHS Trust (2021): ischaemic injury to foot while on paediatric intensive care unit, requiring amputation; Jon represented the claimant, who was resident abroad; application for security for costs successfully resisted.


“He has the intellect for the most complex of cases as well as absolute attention to detail and clarity of advice.”
Chambers & Partners 2024

“He has a brilliant style of advocacy and just the nature of the way he speaks is very persuasive.”
Chambers & Partners 2024

“Jonathan is a really measured, calm practitioner who is very very easy to deal with and brings a real calm to proceedings.”
Chambers & Partners 2024

‘Jon is an excellent advocate – thoughtful, measured and unflappable.’
The Legal 500 2024

“Jonathan is absolutely superb.”
Chambers & Partners 2023

“He is totally unflappable under significant pressure from opponents.”
Chambers & Partners 2023

“Very thorough, excellent at getting to the bottom of complex issues and finding solutions to challenges. A pleasure to work with.”
The Legal 500 2023

“Jonathan is calmness personified and a brilliant advocate”
Chambers & Partners 2022

“He is very intelligent and meticulous”
Chambers & Partners 2022

“An absolutely excellent advocate – he is very measured and very deliberate.”
Chambers & Partners 2022

“Very user-friendly and sensible”
Chambers & Partners 2022

“He’s extremely experienced, knowledgeable and great with clients.”
Chambers & Partners 2021

“An absolute pleasure to work with; he is calm, collected and totally unflappable. He’s also an excellent advocate.” “He approaches cases logically, methodically and thoroughly, which means no stone is left unturned.”
Chambers & Partners 2020

‘He has exceptional advocacy and client handling skills.’
The Legal 500 2019

“Very experienced.” “Hard-working and dedicated.”
Chambers and Partners 2019

‘Incredibly thorough and will leave no stone unturned.’
The Legal 500 2018

‘An extremely effective advocate.’
The Legal 500 2017

“Very measured and very switched-on.” “Approachable, thorough and consistently well prepared. He has a great manner with our clients and is a truly excellent advocate.”
Chambers & Partners 2017

“A thoughtful, steady hand, who instils confidence and has good judgement.”
The Legal 500 2016

“He is a very experienced clinical negligence practitioner who has an excellent grasp of detail.”
Chambers and Partners 2016

“He’s incredibly nice and very thorough.”
Chambers and Partners 2015

‘Perfect for guiding clients through the process.’
The Legal 500 2015

“His advocacy is truly exceptional.”
The Legal 500 2014

Routinely instructed by both claimants and defendants on high-profile, high-value, complex clinical negligence cases. Particularly appreciated for his knowledge of dental cases.  “Very knowledgeable and thorough in his approach. He spends time on cases and puts in a lot of hard work – you can trust his advice.”
Chambers and Partners 2014

Jonathan Holl-Allen is “an excellent advocate.” Commentators say that he is “highly professional, very steady and adept at advising across a range of issues.”
Chambers and Partners 2013

Jonathan Holl-Allen ‘readily grasps the issues at stake’.
The Legal 500 2012

“Jonathan Holl-Allen shows particular skill handling claims involving cerebral palsy and failure to diagnose illnesses”
Chambers and Partners 2011

Jonathan Holl-Allen “whose “calm and methodical approach lends authority to his advocacy”.  Solicitors believe that “his judgment in presenting cases both orally and in writing is excellent”
Chambers and Partners 2010


Jon is a Contributing Editor to the Medical Law Reports. He has reported on the following cases:

  • O’Connor v The Pennine Acute Hospitals NHS Trust [2015] EWCA Civ 1244 [2016] Med LR 11 Clinical negligence – Intraoperative damage – Sufficiency of evidence – Res ipsa loquitur – Rhesa Shipping heresy – Permission to adduce expert evidence.
  • Cambridge Uni Hospitals NHS Foundation v BF [2016] EWCOP 26 [2016] Med LR 314 Court of Protection – Mental illness – Capacity – Best interests – Life-sustaining treatment causing infertility.
  • NAT v Sec of State for Health [2016] EWHC 2005 (Admin) [2016] Med LR 487 Judicial review – Allocation of NHS budgetary responsibility – Power to commission preventative treatment – Preventative treatment for HIV/AIDS – National Health Service Act 2006, section 1H(2).
  • Border v Lewisham & Greenwich NHS Trust [2015] EWCA Civ 8 [2015] Med LR 48 Clinical negligence – Trespass to the person – Consent – Causation – Amendment of statement of case.
  • A v East Kent Hospitals NHS Foundation Trust [2015] EWHC 1038 (QB) [2015] Med LR 262 Clinical negligence – Consent – Material risk – Wrongful birth – Chromosomal abnormality – Anonymity order.
  • R (Chaudhuri) v GMC [2015] EWHC 6621 (Admin) [2015] Med LR 440 General Medical Council – Time limits – Jurisdiction – Mistake of fact as to dates of events giving rise to allegation – Power to correct decisions vitiated by fundamental mistakes of fact – General Medical Council Fitness to Practise Rules 2004 (SI 2004 No 2608), rule 4(5).
  • Krebs v NHS Commissioning Board [2013] EWHC 3474 (Admin) [2014] Med LR 70 General dental practitioner – Contract – Contract for the provision of dental services under the NHS – Breach of contract – Termination of contract – Whether private and public law remedies available to dental contractor – Whether article 1 of First Protocol to ECHR engaged by termination of contract.
  • R (Blue Bio) v Secretary of State for Health [2014] EWHC 1679 (Admin) [2014] Med LR 233 Pharmaceuticals – Medicinal products – Food supplements – Meaning of “medicinal product” for the purposes of the Medicines Directive (2001/83/EC) – To what extent products containing glucosamine “medicinal products” for purposes of Directive – Whether MHRA policy in respect of such products unlawful.
  • Chakrabarty v Ipswich Hospitals NHS Trust [2014] EWHC 2735 (QB) [2014] Med LR 379 Employment – Breach of contract – Contractual disciplinary procedures – Capability – Maintaining High Professional Standards in the Modern NHS (“MHPS”) – Relationship between NCAS assessments, GMC Fitness to Practise procedures and internal disciplinary process – Injunctive relief